A PA34-200 student reported loss of communication when 6 NM northwest of lhm.

Attributes
ACN	572762
Time
Date	200302
Day	Sat
Local Time Of Day	1201 To 1800
Place
State Reference	CA
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nct.tracon tower : ord.tower
Operator	general aviation : personal
Make Model Name	PA-34-200 Seneca I
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : nct.tracon
Flight Phase	cruise : level
Person 1
Affiliation	other
Function	instruction : trainee
Qualification	pilot : private
Experience	flight time last 90 days : 70 flight time total : 100 flight time type : 6
ASRS Report	572767
Person 2
Affiliation	other
Function	instruction : instructor
Events
Anomaly	aircraft equipment problem : critical inflight encounter : weather non adherence : clearance non adherence : far other spatial deviation
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment flight crew : took evasive action
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft Weather
Primary Problem	Ambiguous

Narrative:

My instructor and I were on an IFR flight plan from kemt to klhm. I was in IFR training and multi-engine training. After completing most of the journey, at least until the handoff to sierra approach, all radios, xponders, and altimeters were functioning properly. While being vectored by sierra approach, we were heading on a bearing that, in a few more mins, would have led us into the western side of the sierra nevadas. My instructor advised me to contact sierra approach to ensure continuance on last assigned heading. I did, and there was no reply. I heard other aircraft talking, so I tried again. No answer. My instructor tried our other radio. No answer. He tried his handheld. No response. All xmissions were heard via onboard radios. Still no answer. We input '7600' as a squawk code and looked at our VFR charts for terrain considerations. Terrain was approaching. We turned around and climbed to clear IMC. At this time, squawk code must have been recognized, as we were broadcasting in the blind our intentions. Another aircraft in the air was relaying messages to us from sierra approach. We were instructed immediately to pull up. We did. Then we were vectored in via relay plane, to land, using the ILS approachs at lhm. Another time we were relayed to climb. They stated we were at 800 ft. However, both our altimeters were set to the proper altimeter setting and were showing 2200 ft descending to 1800 ft to the next step down. All approach/landing conditions were preset and we landed. Immediately, someone came out of the hangar to give us a number to call sierra approach. My instructor called and spoke to a controller. All was well. We then departed VFR back to kemt. Our altimeter, with the proper setting, was within 75 ft of field elevation. While arriving in the class delta airspace of kemt, we were idented via our mode C by ATC. All communications were fine. The next business day after landing, the rental aircraft communications were checked. No problems were found. This loss of communication was a complete mystery.

Original NASA ASRS Text

Title: A PA34-200 STUDENT RPTED LOSS OF COM WHEN 6 NM NW OF LHM.

Narrative: MY INSTRUCTOR AND I WERE ON AN IFR FLT PLAN FROM KEMT TO KLHM. I WAS IN IFR TRAINING AND MULTI-ENGINE TRAINING. AFTER COMPLETING MOST OF THE JOURNEY, AT LEAST UNTIL THE HDOF TO SIERRA APCH, ALL RADIOS, XPONDERS, AND ALTIMETERS WERE FUNCTIONING PROPERLY. WHILE BEING VECTORED BY SIERRA APCH, WE WERE HEADING ON A BEARING THAT, IN A FEW MORE MINS, WOULD HAVE LED US INTO THE WESTERN SIDE OF THE SIERRA NEVADAS. MY INSTRUCTOR ADVISED ME TO CONTACT SIERRA APCH TO ENSURE CONTINUANCE ON LAST ASSIGNED HDG. I DID, AND THERE WAS NO REPLY. I HEARD OTHER ACFT TALKING, SO I TRIED AGAIN. NO ANSWER. MY INSTRUCTOR TRIED OUR OTHER RADIO. NO ANSWER. HE TRIED HIS HANDHELD. NO RESPONSE. ALL XMISSIONS WERE HEARD VIA ONBOARD RADIOS. STILL NO ANSWER. WE INPUT '7600' AS A SQUAWK CODE AND LOOKED AT OUR VFR CHARTS FOR TERRAIN CONSIDERATIONS. TERRAIN WAS APCHING. WE TURNED AROUND AND CLBED TO CLR IMC. AT THIS TIME, SQUAWK CODE MUST HAVE BEEN RECOGNIZED, AS WE WERE BROADCASTING IN THE BLIND OUR INTENTIONS. ANOTHER ACFT IN THE AIR WAS RELAYING MESSAGES TO US FROM SIERRA APCH. WE WERE INSTRUCTED IMMEDIATELY TO PULL UP. WE DID. THEN WE WERE VECTORED IN VIA RELAY PLANE, TO LAND, USING THE ILS APCHS AT LHM. ANOTHER TIME WE WERE RELAYED TO CLB. THEY STATED WE WERE AT 800 FT. HOWEVER, BOTH OUR ALTIMETERS WERE SET TO THE PROPER ALTIMETER SETTING AND WERE SHOWING 2200 FT DSNDING TO 1800 FT TO THE NEXT STEP DOWN. ALL APCH/LNDG CONDITIONS WERE PRESET AND WE LANDED. IMMEDIATELY, SOMEONE CAME OUT OF THE HANGAR TO GIVE US A NUMBER TO CALL SIERRA APCH. MY INSTRUCTOR CALLED AND SPOKE TO A CTLR. ALL WAS WELL. WE THEN DEPARTED VFR BACK TO KEMT. OUR ALTIMETER, WITH THE PROPER SETTING, WAS WITHIN 75 FT OF FIELD ELEVATION. WHILE ARRIVING IN THE CLASS DELTA AIRSPACE OF KEMT, WE WERE IDENTED VIA OUR MODE C BY ATC. ALL COMS WERE FINE. THE NEXT BUSINESS DAY AFTER LNDG, THE RENTAL ACFT COMS WERE CHKED. NO PROBS WERE FOUND. THIS LOSS OF COM WAS A COMPLETE MYSTERY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.